Self-balancing precast beam mounting device for constructional engineering

Abstract

The invention discloses a self-balancing precast beam mounting device for constructional engineering, which comprises hoisting equipment, a bracket is arranged on the hoisting equipment, and a balancing assembly is arranged on the bracket. During trial hoisting, the precast beam can be adjusted to be in a basically horizontal state by adjusting the length and the position of the binding belt, the balance assembly is made to be in a horizontal state, if the precast beam is slightly inclined at the moment, a non-zero included angle exists between the balance assembly and the precast beam, and after trial hoisting adjustment is completed, the precast beam falls back to be placed on the bearing structure; and the balance assembly abuts against the top face of the precast beam, and then formal hoisting is conducted. In the initial stage of hoisting, after the bottom surface of the precast beam is separated from the bearing structure, the levelness of the precast beam is changed under the acting force of the balance assembly, so that the precast beam is finely adjusted through the balance assembly, and the precast beam is in a horizontal state and always kept in the horizontal state until hoisting is finished; and therefore, the correction difficulty of the precast beam during steel bar butt joint or butt joint with a temporary support frame is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of construction engineering, and more particularly to a self-balancing prefabricated beam installation device for construction engineering. Background Art

[0002] Prefabricated buildings usually have beams and columns manufactured in advance in the factory according to the design drawings. Prefabricated beams usually have embedded steel bars, stirrups and other structures. Some prefabricated beams are also equipped with embedded parts for lifting, keyways or shear reinforcement for later cast-in-place, etc. During construction, the prefabricated beams are lifted by a crane on site, aligned and placed on temporary support frames, as well as on the supports or brackets reserved for prefabricated columns. Because the ends of prefabricated beams and prefabricated columns usually have steel bars reserved, these steel bars usually need to be inserted into each other, overlapped or aligned with the sleeve position during lifting. After the steel bars of the prefabricated beams and prefabricated columns are tied, overlapped, welded or mechanically connected (such as sleeve grouting connection), formwork is supported and poured at the nodes to complete the connection of the prefabricated beams and prefabricated columns. Because precast beams are usually slender and have exposed steel bars at their ends that need to be connected, it is necessary to ensure that the precast beams are hoisted horizontally as much as possible during hoisting, so as to facilitate the mutual connection of the precast beams and the precast column steel bars. However, in the prior art, the precast beams are usually hoisted by tying straps to the precast beams, and the center of gravity of the hoisting is manually adjusted when tying the straps to prevent the center of gravity of the precast beams from shifting and sliding off the straps during the hoisting process. It is difficult for the precast beams to be placed on the temporary support frame in a horizontal posture. Usually, they are placed in an inclined state, with one part placed on the temporary support frame first and then the other half. In this way, the bearing capacity requirements for the temporary support frame, especially the temporary support frame that first contacts the precast beam, are relatively high. In addition, hoisting in an inclined state makes it more difficult to connect the precast beams and the precast column steel bars. Therefore, how to make the precast beams self-balance and maintain balance during hoisting to reduce the difficulty of correction when the precast beams are connected to the steel bars or the temporary support frame is a technical problem to be solved by the present invention. Summary of the Invention

[0003] The Summary of the Invention introduces a series of simplified concepts that will be further described in the Detailed Description of the Invention. The Summary of the Invention is not intended to limit the key features and essential features of the claimed technical solution, nor is it intended to determine the scope of protection of the claimed technical solution.

[0004] In order to at least partially solve the above problems, the present invention provides a self-balancing prefabricated beam installation device for construction projects, including: a lifting device, a bracket is provided on the lifting device, and a balancing component is provided on the bracket. When the bracket is connected to the prefabricated beam, the balancing component abuts against the top surface of the prefabricated beam.

[0005] Preferably, the bracket is a rectangular frame, and the top and bottom of the bracket are provided with ears, the ears are located at the four corners of the rectangular bracket, and a mounting beam is provided on the bracket, and the two ends of the mounting beam are respectively connected to the two opposite sides of the bracket, and the balancing component is arranged on the mounting beam.

[0006] Preferably, the balancing assembly consists of a balancing wheel, a connecting member, a first reset member, a movable member and a locking member, the locking member is arranged on the mounting beam, one end of the movable member is arranged on the mounting beam and movably connected to the mounting beam, the other end of the movable member is selectively connected to the locking member, the connecting member passes through the mounting beam and is connected to the movable member, one end of the first reset member is connected to the mounting beam, and the other end is connected to the movable member, the balancing wheel is arranged at the bottom of the connecting member and selectively abuts against the top surface of the prefabricated beam.

[0007] Preferably, the movable member is rod-shaped, one end of the movable member is movably connected to the top surface of the mounting beam, a slide groove is provided on the bottom surface of the movable member, and the top of the connecting member is located in the slide groove.

[0008] Preferably, the connecting member consists of a vertical rod and at least four horizontal rods, the four horizontal rods are arranged in a cross shape at the bottom of the vertical rod, the balance wheel is arranged on the horizontal rod, the top of the vertical rod passes through the mounting beam and extends into the slide groove, the top of the vertical rod abuts against the inner top of the slide groove, and a limiting ring is provided on the vertical rod, and the limiting ring is located between the mounting beam and the movable part.

[0009] Preferably, the first reset member is sleeved on the vertical rod, the top of the first reset member abuts against the bottom of the limiting ring, and the bottom of the first reset member abuts against the top of the mounting beam.

[0010] Preferably, the balance wheel consists of a fixing member connected to the horizontal rod, an abutment assembly, a transmission assembly, and a second reset member, one end of the transmission assembly is movably connected to the abutment assembly, and the other end is connected to the fixing member through the second reset member, or connected to the horizontal rod through the second reset member.

[0011] Preferably, the abutment assembly consists of two abutment wheels and a transmission shaft, both ends of the transmission shaft are respectively connected to the two abutment wheels, and the transmission assembly is movably connected to the transmission shaft.

[0012] Preferably, the fixing member consists of an adjusting assembly and a limiting plate, the adjusting assembly passes through the horizontal rod, the bottom of the adjusting assembly is connected to the top of the limiting plate, one end of the transmission assembly is movably connected to the transmission shaft, and the other end passes through the limiting plate, the second reset member is sleeved on the transmission assembly, one end of the second reset member abuts against the bottom surface of the limiting plate, and the other end abuts against the transmission assembly.

[0013] Preferably, the transmission assembly consists of a first arm and a second arm, one end of the first arm is movably connected to the transmission shaft, and the other end is connected to one end of the second arm, the other end of the second arm is connected to one end of the second reset member, and the other end of the second reset member is connected to the horizontal rod, a through hole is provided at the connection between the first arm and the second arm, and a fixed shaft passing through the through hole is provided on the fixing member.

[0014] Compared with the prior art, the present invention has at least the following beneficial effects:

[0015] During a trial hoist, the precast beam is adjusted to a basically horizontal state by adjusting the length and position of the binding straps, and the balancing assembly is kept horizontal. At this time, if the precast beam is slightly tilted, a non-zero angle will exist between the balancing assembly and the precast beam. After the trial hoist adjustment is completed, the precast beam is lowered and placed on the load-bearing structure, and the balancing assembly is brought into contact with the top surface of the precast beam before formal hoisting. In the initial stage of hoisting, after the bottom surface of the precast beam is separated from the load-bearing structure, the precast beam's horizontality changes under the force of the balancing assembly, thereby achieving fine-tuning of the precast beam through the balancing assembly to keep the precast beam in a horizontal state and maintain this horizontal state until the end of the hoisting, thereby reducing the difficulty of correcting the precast beam when docking with steel bars or temporary support frames.

[0016] The self-balancing prefabricated beam installation device for construction engineering described in the present invention, and other advantages, objectives and features of the present invention will be reflected in part through the following description, and in part will be understood by technical personnel in this field through research and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0018] Figure 1 This is a schematic diagram of the self-balancing prefabricated beam installation device for construction engineering according to the present invention.

[0019] Figure 2 Schematic diagram of the balancing component on the bracket.

[0020] Figure 3 It is a schematic diagram of the locking part and the movable part after being locked.

[0021] Figure 4 Schematic diagram of the balancing component on the bracket.

[0022] Figure 5 for Figure 4 Schematic diagram at point A in the middle.

[0023] Figure 6 This is a front view of a first embodiment of a balance wheel.

[0024] Figure 7 Schematic diagram of the second embodiment of the balance wheel.

[0025] Figure 8 This is a front view of a second embodiment of a balance wheel.

[0026] In the figure: 1 lifting equipment, 2 bracket, 21 mounting beam, 3 balancing assembly, 4 prefabricated beam, 5 balancing wheel, 51 fixing part, 511 adjusting assembly, 512 limiting plate, 513 fixed shaft, 52 abutting assembly, 521 abutting wheel, 522 transmission shaft, 53 transmission assembly, 531 first arm, 532 second arm, 54 second reset part, 6 connecting part, 61 vertical rod, 62 horizontal rod, 63 limiting ring, 7 first reset part, 8 movable part, 81 slide groove, 9 locking part. DETAILED DESCRIPTION

[0027] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments so that those skilled in the art can implement the invention with reference to the description.

[0028] It should be understood that terms such as “having”, “including” and “comprising” used herein do not preclude the existence or addition of one or more other elements or combinations thereof.

[0029] like Figures 1-8 As shown, the present invention provides a self-balancing prefabricated beam installation device for construction engineering, comprising: a hoisting device 1, the hoisting device 1 is a prior art, the hoisting device 1 is provided with a bracket 2, the bracket 2 is provided with a balancing component 3, the bracket 2 is generally a rectangular frame, the top and bottom of the bracket 2 are provided with lifting ears, and the lifting ears are located at the four corners of the rectangular bracket 2, as shown in FIG. Figure 2 As shown, a flexible connector or a rigid connector for lifting is provided on the lifting ear, such as a strap, a cable or a connecting rod. The flexible connector or the rigid connector located at the top of the bracket 2 is connected to the lifting equipment 1, and the strap or cable located at the bottom of the bracket 2 is connected to the lifting ear on the prefabricated beam 4. A mounting beam 21 is provided on the bracket 2, and the two ends of the mounting beam 21 are respectively connected to the two opposite sides of the bracket 2 (usually the two short sides of the rectangular frame), so that the mounting beam 21 will not affect the lifting of the prefabricated beam 4, and the balancing component 3 is provided on the mounting beam 21.

[0030] When the bracket 2 is connected to the prefabricated beam 4 and the bottom of the prefabricated beam 4 is separated from the bearing structure, the balancing assembly 3 abuts against the top surface of the prefabricated beam 4 .

[0031] The working principle and beneficial effects of the above technical solution: Through the design of the above structure, when conducting a trial hoisting, the precast beam 4 is adjusted to a basically horizontal state by adjusting the length and position of the binding straps, and the balance component 3 is in a horizontal state. At this time, if the precast beam 4 is slightly tilted, there will be a non-zero angle between the balance component 3 and the precast beam 4. After the trial hoisting adjustment is completed, the precast beam 4 is dropped back and placed on the bearing structure, and the balance component 3 is abutted against the top surface of the precast beam 4, and then the formal hoisting is carried out. At the initial stage of hoisting, after the bottom surface of the precast beam 4 is separated from the bearing structure, the levelness of the precast beam 4 changes under the action of the balance component 3, thereby achieving fine-tuning of the precast beam 4 through the balance component 3, so that the precast beam 4 is in a horizontal state, and always maintains a horizontal state until the end of the hoisting, thereby reducing the difficulty of correction of the precast beam 4 when docking with steel bars or docking with temporary support frames.

[0032] Furthermore, the balancing assembly 3 is composed of a balancing wheel 5, a connecting member 6, a first reset member 7, a movable member 8 and a locking member 9, as shown in FIG. Figure 2 As shown, the locking member 9 is arranged on the mounting beam 21, and one end of the movable member 8 is arranged on the mounting beam 21 and is movably connected to the mounting beam 21. Usually, the movable member 8 and the mounting beam 21 are connected by a pin shaft, so that the movable member 8 can be flipped relative to the mounting beam 21. Figure 2 As shown, it should be noted that the pin connection is only one of the many implementation methods for the movable connection between the movable part 8 and the mounting beam 21. The movable part 8 and the mounting beam 21 can also be in the form of a snap connection. When the prefabricated beam 4 is undergoing a trial hoisting, the movable part 8 is not connected to the locking member 9. At this time, the movable part 8 can move relative to the mounting beam 21. When preparing for formal hoisting, the other end of the movable part 8 is connected and locked to the locking member 9, thereby providing sufficient downward pressure for the balance wheel 5, the connecting member 6 and the first reset member 7. The locking member 9 is a commercially available product or existing technology that can limit the movement of the movable part 8. For example, the locking member 9 can be in the form of a snap or a threaded form.

[0033] The connecting member 6 passes through the mounting beam 21 and is connected to the movable member 8. One end of the first reset member 7 is connected to the mounting beam 21, and the other end is connected to the movable member 8. The balancing wheel 5 is arranged at the bottom of the connecting member 6. When the movable member 8 is not locked with the locking member 9, the balancing wheel 5 does not contact the top surface of the prefabricated beam 4; when the movable member 8 is locked with the locking member 9, the balancing wheel 5 abuts against the top surface of the prefabricated beam 4 and applies a force to the top surface of the prefabricated beam 4.

[0034] Furthermore, the movable member 8 is rod-shaped, one end of the movable member 8 is movably connected to the top surface of the mounting beam 21 , a slide groove 81 is provided on the bottom surface of the movable member 8 , and the top of the connecting member 6 is located in the slide groove 81 .

[0035] Furthermore, the connecting member 6 is composed of a vertical rod 61 and at least four horizontal rods 62, and the four horizontal rods 62 are arranged at the bottom of the vertical rod 61 in a cross shape, as shown in FIG. Figure 2 As shown, the balance wheel 5 is arranged on the horizontal rod 62, and the top of the vertical rod 61 passes through the mounting beam 21 and extends into the slide groove 81. The top of the vertical rod 61 is generally hemispherical. Figure 4 As shown, the top of the vertical rod 61 abuts against the inner top of the slide groove 81, and the hemispherical top makes the vertical rod 61 slide more smoothly in the slide groove 81. A limit ring 63 is provided on the vertical rod 61, and the limit ring 63 is located between the mounting beam 21 and the movable part 8. The limit ring 63 and the vertical rod 61 can be movably connected (for example, a threaded connection, so that the position of the limit ring 63 on the vertical rod 61 is adjustable), or can be fixedly connected.

[0036] The first reset member 7 is sleeved on the vertical rod 61, the top of the first reset member 7 abuts against the bottom of the limiting ring 63, and the bottom of the first reset member 7 abuts against the top of the mounting beam 21. Figure 4 As shown, the first restoring member 7 can usually be a spring.

[0037] The balancing wheel 5 is composed of a fixing member 51 connected to the horizontal rod 62, an abutting assembly 52, a transmission assembly 53, and a second reset member 54. The fixing member 51 is used to connect and fix the balancing wheel 5 to the horizontal rod 62. The abutting assembly 52 is used to contact the top surface of the precast beam 4 and transmit pressure to the top surface of the precast beam 4 when pressure is applied to the top surface of the precast beam 4. One end of the transmission assembly 53 is movably connected to the abutting assembly 52. ​​Depending on the embodiment, the other end of the transmission assembly 53 is connected to the fixing member 51 via the second reset member 54 (see the first embodiment below for details), or connected to the horizontal rod 62 via the second reset member 54 (see the second embodiment below for details).

[0038] Furthermore, the abutment assembly 52 is composed of two abutment wheels 521 and a transmission shaft 522. The two ends of the transmission shaft 522 are respectively connected to the two abutment wheels 521. The transmission assembly 53 is movably connected to the transmission shaft 522. Through the abutment wheel 521, when the inclined prefabricated beam 4 is pressurized and adjusted to be horizontal, the abutment assembly 52 can generate relative movement with the prefabricated beam 4 while providing pressure.

[0039] Further, the fixing member 51 is composed of an adjusting component 511 and a limiting plate 512. The adjusting component 511 penetrates through the horizontal rod 62. The bottom of the adjusting component 511 is connected to the top of the limiting plate 512. The adjusting component 511 can be composed of a fixing block, a screw, and a nut. The fixing block is arranged on the horizontal rod 62, as Figure 5 shown. The screw is threadedly connected to the fixing block. The bottom of the screw penetrates through the fixing block and is threadedly connected to the top surface of the limiting plate 512. The nut is sleeved on the screw and is located at the bottom of the fixing block. The transmission component 53 is composed of a "丄"-shaped sliding rod and a mounting plate. Arc-shaped grooves adapted to the transmission shaft 522 are provided at the bottom of the sliding rod and the top of the mounting plate. The mounting plate is connected to the bottom of the sliding rod by screws. The transmission shaft 522 is located in the arc-shaped groove, so that one end of the transmission component 53 away from the horizontal rod 62 is movably connected to the transmission shaft 522. The other end of the transmission component 53 (that is, the end of the sliding rod away from the mounting plate) penetrates through the limiting plate 512 and is movably connected to the limiting plate 512. The end of the sliding rod away from the mounting plate can also penetrate through the fixing block and be slidably connected to the fixing block. A nut can be provided at the end of the sliding rod away from the mounting plate to prevent the sliding rod from falling off the limiting plate 512 (or the fixing block). The second resetting member 54 is sleeved on the transmission component 53. In this embodiment, the second resetting member 54 is usually a compression spring. One end of the second resetting member 54 abuts against the bottom surface of the limiting plate 512, and the other end abuts against the transmission component 53, as Figure 5 shown.

[0040] In the foregoing embodiment, we provided a balance wheel 5 that applies pressure in the vertical direction. Because the elastic force of the second resetting member 54 is adjustable (that is, the distance between the limiting plate 512 and the bottom of the transmission component 53 is adjustable), the fine adjustment of the levelness of the precast beam 4 in the foregoing embodiment is more accurate. However, this embodiment requires more components, and the production and assembly are relatively complex. For this reason, we provide another embodiment.

[0041] In this embodiment, the fixing member 51 is a steel plate welded to the horizontal rod 62. The transmission assembly 53 is composed of a first arm 531 and a second arm 532. One end of the first arm 531 is movably connected to the transmission shaft 522, and the other end is connected to one end of the second arm 532. The other end of the second arm 532 is connected to one end of the second reset member 54, and the other end of the second reset member 54 is connected to the horizontal rod 62. In this embodiment, the second reset member 54 is usually a tension spring. In order to facilitate the installation of the tension spring, a steel plate connected to the end of the tension spring is usually welded on the horizontal rod 62. A through hole is provided at the connection between the first arm 531 and the second arm 532. A fixed shaft 513 passing through the through hole is provided on the fixing member 51, so that the transmission assembly 53 can rotate around the fixed shaft 513. In order to increase the pressure-bearing capacity of the transmission assembly 53, a non-zero angle is provided between the first arm 531 and the second arm 532, such as Figure 7 and Figure 8 shown.

[0042] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0043] In the present invention, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection, or communication; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0044] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the description and implementation methods. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A self-balancing prefabricated beam installation device for construction engineering, comprising: The hoisting device (1) is characterized in that a bracket (2) is provided on the hoisting device (1), a balancing component (3) is provided on the bracket (2), and when the bracket (2) is connected to the prefabricated beam (4), the balancing component (3) abuts against the top surface of the prefabricated beam (4).

2. The self-balancing prefabricated beam installation device for construction engineering according to claim 1, characterized in that: The bracket (2) is a rectangular frame. The top and bottom of the bracket (2) are both provided with hanging ears, and the hanging ears are located at the four corners of the rectangular bracket (2). A mounting beam (21) is provided on the bracket (2). The two ends of the mounting beam (21) are respectively connected to two opposite sides of the bracket (2). The balancing component (3) is provided on the mounting beam (21).

3. The self-balancing prefabricated beam installation device for construction engineering according to claim 2, characterized in that: The balancing assembly (3) is composed of a balancing wheel (5), a connecting member (6), a first reset member (7), a movable member (8) and a locking member (9); the locking member (9) is arranged on the mounting beam (21); one end of the movable member (8) is arranged on the mounting beam (21) and is movably connected to the mounting beam (21); the other end of the movable member (8) is selectively connected to the locking member (9); the connecting member (6) passes through the mounting beam (21) and is connected to the movable member (8); one end of the first reset member (7) is connected to the mounting beam (21) and the other end is connected to the movable member (8); the balancing wheel (5) is arranged at the bottom of the connecting member (6) and selectively abuts against the top surface of the prefabricated beam (4).

4. The self-balancing prefabricated beam installation device for construction engineering according to claim 3, characterized in that: The movable member (8) is rod-shaped, one end of the movable member (8) is movably connected to the top surface of the mounting beam (21), a slide groove (81) is provided on the bottom surface of the movable member (8), and the top of the connecting member (6) is located in the slide groove (81).

5. The self-balancing prefabricated beam installation device for construction engineering according to claim 4, characterized in that: The connecting member (6) is composed of a vertical rod (61) and at least four horizontal rods (62). The four horizontal rods (62) are arranged in a cross shape at the bottom of the vertical rod (61). The balance wheel (5) is arranged on the horizontal rod (62). The top of the vertical rod (61) passes through the mounting beam (21) and extends into the slide groove (81). The top of the vertical rod (61) abuts against the inner top of the slide groove (81). A limiting ring (63) is provided on the vertical rod (61). The limiting ring (63) is located between the mounting beam (21) and the movable member (8).

6. The self-balancing prefabricated beam installation device for construction engineering according to claim 5, characterized in that: The first reset member (7) is sleeved on the vertical rod (61), the top of the first reset member (7) abuts against the bottom of the limiting ring (63), and the bottom of the first reset member (7) abuts against the top of the mounting beam (21).

7. The self-balancing prefabricated beam installation device for construction engineering according to claim 5, characterized in that: The balance wheel (5) is composed of a fixing member (51) connected to a horizontal rod (62), an abutting assembly (52), a transmission assembly (53), and a second reset member (54). One end of the transmission assembly (53) is movably connected to the abutting assembly (52), and the other end of the transmission assembly (53) is connected to the fixing member (51) through the second reset member (54), or the other end of the transmission assembly (53) is connected to the horizontal rod (62) through the second reset member (54).

8. The self-balancing prefabricated beam installation device for construction engineering according to claim 7, characterized in that: The abutment assembly (52) is composed of two abutment wheels (521) and a transmission shaft (522). Both ends of the transmission shaft (522) are respectively connected to the two abutment wheels (521). The transmission assembly (53) is movably connected to the transmission shaft (522).

9. The self-balancing prefabricated beam installation device for construction engineering according to claim 8, characterized in that: The fixing member (51) is composed of an adjusting component (511) and a limiting plate (512). The adjusting component (511) passes through the horizontal rod (62). The bottom of the adjusting component (511) is connected to the top of the limiting plate (512). One end of the transmission component (53) is movably connected to the transmission shaft (522), and the other end passes through the limiting plate (512). The second reset member (54) is sleeved on the transmission component (53), and one end of the second reset member (54) abuts against the bottom surface of the limiting plate (512), and the other end abuts against the transmission component (53).

10. The self-balancing prefabricated beam installation device for construction engineering according to claim 8, characterized in that: The transmission assembly (53) is composed of a first arm (531) and a second arm (532). One end of the first arm (531) is movably connected to the transmission shaft (522), and the other end is connected to one end of the second arm (532). The other end of the second arm (532) is connected to one end of the second reset member (54). The other end of the second reset member (54) is connected to the horizontal rod (62). A through hole is provided at the connection between the first arm (531) and the second arm (532), and a fixed shaft (513) is provided on the fixing member (51) that passes through the through hole.

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